Wellesley is a town in Norfolk County, Massachusetts, United States. It is part of Greater Boston. The population was 27,982 at the time of the 2010 census. It is best known as the home of Wellesley College, Babson College, and a campus of Massachusetts Bay Community College. Olin College, an engineering school, has a campus that spans from Needham, Massachusetts into Wellesley and is adjacent to Wellesley's Babson College.

Wellesley is located in eastern Massachusetts. It is bordered on the east by Newton, on the north by Weston, on the south by Needham and Dover and on the west by Natick. According to the United States Census Bureau, the town has a total area of 10.49 square miles (27.2 km2), of which, 10.18 square miles (26.4 km2) is land and 0.32 square miles (0.83 km2) is water. The town's historic 19th century inn was demolished to make way for condominiums and mixed-use development in 2006. The Wellesley Country Club clubhouse, which is the building where the town was founded, was demolished in 2008, and a new clubhouse was built. The town's pre-World War II high school building was torn down & replaced, with a brand new high school finished in 2012 and the entire 1960s-style Linden Street strip-mall has been replaced by "Linden Square" – a shopping district that includes a flagship Roche Bros. supermarket, restaurants, cafes, clothing stores, along with a mixture of national chains and local shops.

As of the census of 2000, there were 26,613 people, 8,594 households, and 6,540 families residing in the town. The population density was 2,614.1 people per square mile (1,009.4/km²). There were 8,861 housing units at an average density of 870.4 per square mile (336.1/km²).